A shepherd who was sacked because he could not work while recovering from heart surgery was unjustifiably fired, the Employment Relations Authority has ruled.

The authority said Henry Cooper had a personal grievance for unjustified dismissal with Mt Pember Station owner John Ramsey.

Authority member Michael Loftus ordered Ramsey to pay Cooper $18,500 in lost wages and compensation.

Cooper began working at the North Canterbury farm in May 2012 and had to visit his doctor every few months for a heart condition.

On December 8, 2012, he was struck down by chest pains, unrelated to his previous heart condition, and was airlifted to Christchurch Hospital, where he had heart surgery.

He spent a month in hospital and was told he would need three months' rehabilitation from the time of the surgery before he could return to work.

He repeatedly tried to talk to Ramsey about how best to manage the situation, but each time was met with hostility and avoidance.

On January 15 last year, Cooper received a letter from Anne Kelly, general manager of the FJ Ramsey group of companies, asking for a medical certificate with a time frame for rehabilitation so they could have a meeting on what would happen next.

Cooper provided the information, stating the three-month rehabilitation time frame, although his doctor mentioned that Cooper would probably try to go back to work much earlier than this.

No arrangement for a meeting was forthcoming from either Ramsey or Kelly.

They considered the documentation and fired Cooper on January 29 with seven days' notice, saying they could not accommodate his rehabilitation because it would put too much stress on other staff.

On the day the notice expired, Cooper went back to his doctor, who said he was cleared for light duties.

He attempted to tell Ramsey this, but he said Kelly was now handling the issue and she was on holiday.

Cooper's dismissal was final, so he filed his grievance.

Loftus ruled that the sacking was unjustified for two reasons.

First, neither Ramsey nor Kelly held a meeting with Cooper after he provided his rehabilitation information.

Ramsey told the authority's hearing that this was not necessary as the documentation Cooper provided was comprehensive.

Loftus concluded that this explanation was inadequate and a meeting should have been held.

The other reason for firing Cooper, that the farm could not cope with the increased workload he left, was found to be incorrect, Loftus said.

Several workers told the hearing that the farm was operating as normal during Cooper's absence.